Zhou R, Wu Z, Cao X, Jiang F L
Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in East China, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China.
Genet Mol Res. 2015 Oct 30;14(4):13868-79. doi: 10.4238/2015.October.29.7.
In the current study, morphological traits and molecular markers were used to assess the genetic diversity of 29 cultivated tomatoes, 14 wild tomatoes and seven introgression lines. The three components of the principal component analysis (PCA) explained 78.54% of the total morphological variation in the 50 tomato genotypes assessed. Based on these morphological traits, a three-dimensional PCA plot separated the 50 genotypes into distinct groups, and a dendrogram divided them into six clusters. Fifteen polymorphic genomic simple- sequence repeat (genomic-SSR) and 13 polymorphic expressed sequence tag-derived SSR (EST-SSR) markers amplified 1115 and 780 clear fragments, respectively. Genomic-SSRs detected a total of 64 alleles, with a mean of 4 alleles per primer, while EST-SSRs detected 52 alleles, with a mean of 4 alleles per primer. The polymorphism information content was slightly higher in genomic-SSRs (0.49) than in EST-SSRs (0.45). The mean similarity coefficient among the wild tomatoes was lower than the mean similarity coefficient among the cultivated tomatoes. The dendrogram based on genetic distance divided the 50 tomato genotypes into eight clusters. The Mantel test between genomic-SSR and EST-SSR matrices revealed a good correlation, whereas the morphological matrices and the molecular matrices were weakly correlated. We confirm the applicability of EST-SSRs in analyzing genetic diversity among cultivated and wild tomatoes. High variability of the 50 tomato genotypes was observed at the morphological and molecular level, indicating valuable tomato germplasm, especially in the wild tomatoes, which could be used for further genetic studies.
在本研究中，利用形态学性状和分子标记评估了29个栽培番茄、14个野生番茄和7个渐渗系的遗传多样性。主成分分析（PCA）的三个成分解释了所评估的50个番茄基因型中78.54%的总形态变异。基于这些形态学性状，三维PCA图将50个基因型分为不同的组，聚类图将它们分为六个簇。15个多态性基因组简单序列重复（基因组SSR）和13个多态性表达序列标签衍生SSR（EST-SSR）标记分别扩增出1115个和780个清晰片段。基因组SSR共检测到64个等位基因，每个引物平均4个等位基因，而EST-SSR检测到52个等位基因，每个引物平均4个等位基因。基因组SSR的多态性信息含量（0.49）略高于EST-SSR（0.45）。野生番茄之间的平均相似系数低于栽培番茄之间的平均相似系数。基于遗传距离的聚类图将50个番茄基因型分为八个簇。基因组SSR和EST-SSR矩阵之间的Mantel检验显示出良好的相关性，而形态学矩阵和分子矩阵之间的相关性较弱。我们证实了EST-SSR在分析栽培番茄和野生番茄遗传多样性方面的适用性。在形态学和分子水平上观察到50个番茄基因型具有高度变异性，表明存在有价值的番茄种质，特别是野生番茄中的种质，可用于进一步的遗传学研究。
